Lithium-ion Battery Swelling Control via Electrolyte Degassing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium ion secondary batteries with flexible outer cases are prone to swelling due to dissolved gases like nitrogen and carbon dioxide in the electrolytic solution, which can lead to safety issues and compromised sealing properties during high-temperature aging.
Innovation Solution
A method for manufacturing lithium ion secondary batteries involves subjecting the electrolytic solution to decompression treatment to reduce dissolved nitrogen levels to 100 µg/mL or less, thereby preventing swelling and improving sealing properties by injecting the treated solution into the battery cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If flexible films are used for the outer case to reduce weight, then the battery becomes lightweight, but the outer case becomes vulnerable to impact and swells significantly when gas is generated
Solution Approach 1:
The patent changes the physical-chemical parameters of the electrolytic solution by controlling the dissolved gas content (nitrogen, carbon dioxide) to 100 µg/mL or less through decompression treatment. This parameter change prevents gas generation that would cause swelling of the flexible outer case, thereby maintaining both lightness and reliability.
2Quantity of substance
If impurity removal techniques are applied in electrolytic solution manufacturing, then NH3 and H2 can be temporarily removed, but moisture, nitrogen, and carbon dioxide dissolve in the electrolytic solution before injection
Solution Approach 1:
The patent applies decompression treatment to the electrolytic solution before injection into the battery cell. This preliminary action removes dissolved gases (nitrogen, carbon dioxide) in advance, preventing subsequent swelling issues that would occur during battery operation or storage.
Solution Approach 2:
The patent changes the physical-chemical parameters of the electrolytic solution by controlling the dissolved gas content (nitrogen, carbon dioxide) to 100 µg/mL or less through decompression treatment. This parameter change prevents gas generation that would cause swelling of the flexible outer case, thereby maintaining both lightness and reliability.
3Reliability
If nitrogen gas is used to fill the container during electrolytic solution transport, then moisture contamination is prevented, but a large amount of nitrogen dissolves in the electrolytic solution causing swelling during high-temperature aging
Solution Approach 1:
The patent applies decompression treatment to the electrolytic solution before injection into the battery cell. This preliminary action removes dissolved gases (nitrogen, carbon dioxide) in advance, preventing subsequent swelling issues that would occur during battery operation or storage.
Solution Approach 2:
The patent changes the physical-chemical parameters of the electrolytic solution by controlling the dissolved gas content (nitrogen, carbon dioxide) to 100 µg/mL or less through decompression treatment. This parameter change prevents gas generation that would cause swelling of the flexible outer case, thereby maintaining both lightness and reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively suppresses battery swelling at high temperatures and enhances sealing integrity by minimizing bubble generation during the vacuum-impregnation process, ensuring improved safety and performance.
Implementation Method 1
it is evacuated into a prescribed vacuum degree in the battery case, a temporary liquid storing chamber of an injection hopper in which a prescribed amount of an organic electrolytic solution is evacuated into the vacuum degree
Implementation Method 2
a pressure difference higher by a prescribed value to a pressure in the battery case is generated, and by opening an injection port of the injection hopper, the organic electrolytic solution of the temporary liquid storing chamber is injected into the battery case via the injection port and the injection nozzle by the pressure difference
Data Source
Figure 1~3
Figure 4A~5A
Figure 5B
AI summary
A method for manufacturing a lithium ion secondary battery, the lithium ion secondary battery including a positive electrode and a negative electrode disposed with a separator sandwiched therebetween and contained together with an electrolytic solution in an outer case including a flexible film, wherein the quantity of dissolved nitrogen in the electrolytic solution in injecting the electrolytic solution into the outer case is 100 µg/mL or less.